Hadron-hadron interactions from Nf = 2 + 1 + 1 lattice QCD: isospin-2 ππ scattering length

Abstract

Abstract: We present results for the I = 2 ππ scattering length using Nf = 2 + 1 + 1 twisted mass lattice QCD for three values of the lattice spacing and a range of pion mass values. Due to the use of Laplacian Heaviside smearing our statistical errors are reduced compared to previous lattice studies. A detailed investigation of systematic effects such as discretisation effects, volume effects, and pollution of excited and thermal states is performed. After extrapolation to the physical point using chiral perturbation theory at NLO we obtain Mπa0 = − 0.0442(2)stat(− 0+ 4)sys.[Figure not available: see fulltext.]